A complementary Magnetic Tunneling Junction (MTJ) device can provide larger sensing margin than a single MTJ bit-cell based device. However, complementary MTJ based memory bit-cells may suffer from uncertain read issues when retention error occurs upon a read mode. Retention error generally refers to an error when one of the MTJs in the complementary MTJ based memory bit-cell is flipped resulting in a conflicting sensing mode with two MTJs storing the same values.
One way to solve this issue is to employ a second read mode (also referred to as the “Salvage Mode”), which identifies the confliction by reading the two MTJs (of the complementary MTJ bit-cell) separately. However, the second read mode requires complicated reading logic which increases reading latency.